Mike, thanks so much for your reply.
I am thoroughly confused… I added that code to both share-config & share-config-custom, restarted Alfresco, and nothing changed in the UI. The only way to get something to happen is if I add a line to workflow.get.html.ftl. And all that does is add my workflow to the dropdown in Share. I need Share to understand my entire workflow, the way Alfresco Explorer does. My processdefinition and model code and what-not are all in tomcat/webapps/alfresco/WEB-INF/classes/alfresco/extension. What is the best way for Share to understand my advanced custom workflow?
I appreciate your advice! Thanks again.